River on guard

[Maethmaenor]

Hello:

I am pretty sure that I knew the answer to this, as I believe it was discussed in the disappeared German Forum (Das Tolkien-Board, it was good!) years ago, but now I can't remember and can't find similar discussions here or in the errata or in the rules. So, sorry if it is too basic:

Can be River be played on guard?. I think, if on guard, it may be revealed an on-guard card in the same chain of effects in response to the play (declaration thereof) of any item, faction, ally, or other card that potentially taps the site, because it affects the company or a character in the company that site phase, as in case #2 of the revised rule for on guard cards.

But, if so revealed, the card text says that the company must do nothing during its site phase, but it has done already something in the site phase, specifically it has entered the site, facing the aa. I know that a revealed on-guard card retroactively takes effect as though it had been both declared and resolved immediately prior to the chain of effects during which it was revealed, but with this the card would only avoid that the company plays an item (for example), but would not avoid the already faced aa.

RIVER
Short‐event
Playable on a site. If a company that has moved to this site this turn does not tap a ranger, it must do nothing during its site phase.

[Bandobras Took]

A card cannot be revealed that:
Returns a company to its site of origin.
Taps a company's site.
Potentially removes a character from a company, besides combat or corruption checks.
Forces a company to do nothing during its site phase.
Directly taps a character in the company.

[Khamul the Easterling]

... may I add the link to the German Errata list, where this is covered, too ....
http://www.velanar.de/lotr/files/MECCG-Errata6.pdf

[Maethmaenor]

...and here appears Khamûl, an old Gefährte at the Tolkien Board. Ich grüße dich!

Thanks both, I have re-read the material, the CRF too, but I forgot that that was highlighted by Bandobras. I should have verified not only rules and card errata, but the CRF about on guard cards, too.
It was point 4) in the new rule for OG cards in the edited version of METW rules... So

I will download your errata and rules too, Khamûl.

Regards.